PC PROGRAM FOR COMPARING TRACKING INDEXES IN SEVERAL INDEPENDENT GROUPS

A method for computing a measure of tracking based on Cohen's kappa statistic for one-sample longitudinal data sets was previously described and implemented. This paper shows how one may test the equality of several kappas, each computed from an independent longitudinal sample. Thus, it is possible to formally compare groups of individuals with regard to stability in growth (or adaptive) patterns. Relative assessments of predictability in growth outcomes in different populations can be made with this approach. Also, when a common value of kappa is not contradicted by the data, a method to estimate this value and obtain a confidence interval for it is shown. A menu-driven GAUSS program for carrying out the procedure is described and made available. The method and program are illustrated with three samples of Guatemalan children.